The present invention relates to a variable resistor with a slider, and more particularly, to the shape of its slider.
Conventionally, there has been proposed, for instance, a variable resistor shown in FIG. 7 through FIG. 9, wherein an approximately circular arc-shaped resistor 2 corresponding to the portions of dotted lines in FIG. 7 is provided on the base plate 1, the cylindrical portion 8a of a terminal 8 positioned in a central hole 1a of the base plate 1 is caulked so that a slider 3 is rotated mounted on the base plate 1. The slider 3 has a projection 4a of an arm portion 4 formed in a circular arc shape in one portion of the outer periphery contacted against the resistor 2, and has a groove portion 5 which is adjustable to move by a minus driver. Also, outer electrodes 2a, 2a are respectively connected with both ends of the resistor 2.
However, this has a problem that the deformation of the arm portion 4 is likely to occur through the application of an outer force at the engagement with counterpart such as a circuit base plate or in the adjustment of the slider, thus causing inferior contact of the projection 4a, because there is nothing to guard the arm portion 4. In addition, there is a problem about the reliability of press being low with respect to the slider 3 since an area to be sucked by a chip-pressor is relatively small.
As to another example, a variable resistor has also been known, as shown in FIG. 10 through FIG. 12, wherein a rotor 6 retained on the cylindrical portion 8a of the terminal 8 is rotatably disposed integrally with the slider 3. It is to be noted that in FIG. 10 through FIG. 12 the same reference numerals are given to the same parts as those of the conventional variable resistor of FIG. 7 through FIG. 9. This variable resistor has advantages that the deformation of the arm portion 4 is rarely to occur because the arm portion 4 is guarded by the rotor 6, and the adjustment is easier to perform because the groove 7 formed in the rotor 6 is adjustable by the pulse driver. However, this variable resistor has new problems that the height of this variable resistor is increased by the portion of the rotor 6 provided, and furthermore the number of the parts increases to make it difficult to position the rotor 6, with a new problem that the cost is absolutely increased on the whole, thus causing the increase of the cost on the whole.